We were working on a backup also in case something went awry with one of the skins. It was simultaneously developed but is currently very unfinished. We wanted to make sure we were going to have a full team comp and there were concerns that one of the skins was more risky. Hence the backup in case that had happened.

I FOUND THE SYMBOL (along with some others on the forums)
Lunari Symbol, this can only mean one thing, Pool Party Diana confirmed

Hey Parrot! Will the Pool Party become an annual event like the Harrowing, Snowdown Showdown, and Lunar Revel? Any info on if there will be a bundle with these 4(and possibly Pool Party Ziggs), or can one of the e-commerce dudes answer that?

We were working on a backup also in case something went awry with one of the skins. It was simultaneously developed but is currently very unfinished. We wanted to make sure we were going to have a full team comp and there were concerns that one of the skins was more risky. Hence the backup in case that had happened.

So was the one that didn't make it the risky one that proved undoable or the backup that ended up not being needed? Are you able to say which one was the risky one and why? I'm curious if it was risky from a creative or technical standpoint (I could see Lee Sin being risky in regards to needing to make another new fighting style set of animations).

We were working on a backup also in case something went awry with one of the skins. It was simultaneously developed but is currently very unfinished. We wanted to make sure we were going to have a full team comp and there were concerns that one of the skins was more risky. Hence the backup in case that had happened.